You can dilute a sample of your pool water 1:1 with distilled water, and re-test your CYA with that, and just multiply your result x 2 to get a ballpark CYA number. Once you have that, you have two options..1) is to drain and refill some water to lower that CYA level (although with a SWCG, most of them call for it to be around 80 ppm, so check your owner's manual before making that call), or 2) just run a high CYA/high chlorine pool. If you'll take a look at the info here, it will explain more and give you the chlorine levels you'll need to expect to run with a high CYA pool http://www.poolforum.com/pf2/forumdi...ting-Chemicals. If you can't follow the link, then log out, go to the main forum page, and look for the subforum called "Using chlorine and chlorinating chemicals". Then click on the 2nd sticky called "Best Guess Chlorine Chart". Personally, I run a high CYA pool on purpose. In my climate, with full sun, I find that I use much less chlorine if I keep the pool highly stabilized. The pool people will tell you that you can't do that, that at some point your stabilizer "won't work" and you'll have "chlorine lock", but I've been doing it with no problems for 11 years now, so I know better. The best guess chart will explain more.

Your calcium hardness level may or may not be important, depending on what kind of pool you have. If you have plaster, concrete, gunite, etc, that uses plaster or concrete in the mix, then it is crucial to know your calcium levels so that the water doesn't leach the calcium out of your decking. However, you may be able to just get the pool store to test that for you, if you're not using any calcium-based form of chlorine like cal-hypo. (Just be prepared for them to try to sell you a list of stuff--just resist, smile, and tell them that you have it all at home.). If you can take pics of your pool and upload them to flickr, photobucket, or one of those picture hosting websites, you can post a link to the pics here and maybe somebody here on the forum can help you identify what type of pool you have.

So... I've already covered #1, #2, and #4. To address #3, your FC was degraded by sunlight and/or gunk in the pool. Although stabilizer is in the pool water to protect the chlorine from degrading in the sun, it doesn't completely stop it, so you'll still have some slow reduction in FC. If you have goo in the pool, that will also contribute to the reduction in FC.